One of the weaknesses of Gold Open Access publishing (that's the model where open access is provided by a publisher) has been the rise of predatory publishing, where commercial enterprises set up fake journals with the idea of scamming authors or institutions into paying publication fees. Rick Anderson suggest that a blacklist is in order, and identifies four (or maybe five) types of predatory journals: phony journals, such as promotional sock-puppets; pseudo-scholarly journals, which don't do proper peer review and editing; false flag journals, which fool people into thinking they are submitting to legitimate journals; and Masqueraders, which pretend to have an association with a prestigious institution. The possible fifth category is constituted of legitimate journals who are abusing their position by charging predatory prices (Anderson is obviously far less concerned about them).